Vegetable peels as natural antioxidants for processed foods – A review

Abstract

Antioxidants are substances that are able to prevent or inhibit oxidation processes in human body as well as in food products. Oxidation reactions can produce free radicals, which start chain reactions that damage cells. Antioxidants terminate these chain reactions by removing free radical intermediates and inhibit other oxidation reactions by being oxidized it selves. The protection of foods from oxygen is the basic principle upon which antioxidant protective technologies are based. Both synthetic as well as natural antioxidants are using in food industry but the application of synthetics has been reassessed due to its potential carcinogenic effects. Research is being focused on vegetable materials which are a rich source of antioxidant compounds. Various antioxidant compounds have been isolated, many of them being polyphenols. Direct relationship exists between the total phenolic contents and the antioxidant activity in fruits and vegetables. The entire tissue of fruits and vegetables are rich in bio-active compounds and in most cases the waste by-products can present similar or even higher contents of antioxidant compounds. The waste materials such as peels, seeds and stones produced from the fruit and vegetable processing unit can be successfully used as a source of phytochemicals and antioxidants. Different antioxidant sources, their mode of action, application in food industry and antioxidant activities of banana peel, watermelon peel, potato peel and cucumber peel are reviewed in this paper.